Electroluminescent (EL) display panels are known as one type of transmissive display panels including a light-emitting layer that is sandwiched between a front side transmissive film and a rear side transmissive film. The EL display panels use inorganic or organic thin films exhibiting electroluminescence (hereinafter also referred to as “EL”) that emit light when injecting a current, and are provided with a light-emitting layer that is made of such an EL material.
One application of the transmissive display panel is a stereoscopic image display device. For example, provided that a transmissive display panel is positioned in the front of a display panel aligned with a certain distance, the same images are exhibited on these display panels respectively. When a viewer watches the back display panel through the transmissive display panel then he will see the same images as one merged image without recognizing two different images at different depth positions. Based on such a principle, there is a stereoscopic image display device in which the ratio of the brightness (luminance) of two identical images is changed partially so that the merged image is constructed as a stereoscopic image in the viewer's head.
Such a stereoscopic image display device puts little fatigue on the viewer, since it not only eliminates the need for any special 3D glasses, but also allows a more natural stereoscopic display than conventional stereoscopic image display devices.
Generally when a display panel displaying an image is viewed through a transmissive display panel that is aligned therewith at a certain distance in the depth direction, then reflections of the front side panel may occur. That is, the front side image may by reflected by the rear side panel and imaged again onto the front side panel, though the particular phenomenon is not limited to the stereoscopic image display device. As a result the viewed image may become fuzzy even in the stereoscopic image display device.